Atherosclerosis, the principal cause of heart attack, stroke and gangrene of the extremities, is responsible for 50% of all mortality in the USA, Europe and Japan. The lesions result from an excessive, inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall. A large number of growth factors, cytokines and vasoregulatory molecules participate in this process. Our ability to control the expression of genes encoding these molecules and to target specific cell types provides opportunities to develop new diagnostic and therapeutic agents to induce the regression of the lesions and, possibly, to prevent their formation.

The pathogenesis of atherosclerosis: a perspective for the 1990s

In both metazoan development and metastatic cancer, migrating cells must carry out a detailed, complex program of sensing cues, binding substrates, and moving their cytoskeletons. The linker cell in Caenorhabditis elegans males undergoes a stereotyped migration that guides gonad organogenesis, occurs with precise timing, and requires the nuclear hormone receptor NHR-67. To better understand how this occurs, we performed RNA-seq of individually staged and dissected linker cells, comparing transcriptomes from linker cells of third-stage (L3) larvae, fourth-stage (L4) larvae, and nhr-67-RNAi–treated L4 larvae. We observed expression of 8,000–10,000 genes in the linker cell, 22–25% of which were up- or down-regulated 20-fold during development by NHR-67. Of genes that we tested by RNAi, 22% (45 of 204) were required for normal shape and migration, suggesting that many NHR-67–dependent, linker cell-enriched genes play roles in this migration. One unexpected class of genes up-regulated by NHR-67 was tandem pore potassium channels, which are required for normal linker-cell migration. We also found phenotypes for genes with human orthologs but no previously described migratory function. Our results provide an extensive catalog of genes that act in a migrating cell, identify unique molecular functions involved in nematode cell migration, and suggest similar functions in humans.

https://science.sciencemag.org/content/sci/256/5054/184.full.pdf

Alzheimer's disease: the amyloid cascade hypothesis

Epidermal growth factor-related peptides and their receptors in human malignancies

The molecular pathology of Alzheimer's disease.

CEREBRAL deposition of the β-amyloid peptide (Aβ) is an invariant feature of Alzheimer's disease. Since the original isola-tion and characterization of αβ (ref. 1) and the subsequent cloning of its precursor protein2–5, no direct evidence for the actual production of discrete Aβ has been reported6–11. Here we investigate whether Aβ is present in human biological fluids using antibodies specific for an epitope within Aβ that spans the site of normal constitutive cleavage12,13. These antibodies were used to construct a sandwich type enzyme-linked immunosorbent assay that detects Aβ in cerebrospinal fluid, plasma and conditioned medium of human mixed-brain cells grown in vitro (see also ref. 14). By affinity chromatography, we have purified and sequenced Aβ and a novel Aβ fragment from human cerebrospinal fluid and conditioned medium of human mixed-brain cell cultures. These findings demonstrate that Aβ is produced and released both in vivo and in vitro. These observations offer new opportunities for developing diagnostic tests for Alzheimer's disease and therapeutic strategies aimed at reducing the cerebral deposition of Aβ.

Isolation and quantification of soluble Alzheimer's β-peptide from biological fluids

Macrophage-like U-937 cells secrete a 22-kilodalton heparin-binding growth factor that is mitogenic for BALB-3T3 fibroblasts and smooth muscle cells, but not endothelial cells. The amino acid sequence predicted from complementary DNA clones indicates that the mitogen is a new member of the epidermal growth factor (EGF) family. This heparin-binding EGF-like growth factor (HB-EGF) binds to EGF receptors on A-431 epidermoid carcinoma cells and smooth muscle cells, but is a far more potent mitogen for smooth muscle cells than is EGF. HB-EGF is also expressed in cultured human macrophages and may be involved in macrophage-mediated cellular proliferation.

https://science.sciencemag.org/content/sci/251/4996/936.full.pdf

A heparin-binding growth factor secreted by macrophage-like cells that is related to EGF.

The amyloid proteins isolated from neuritic plaques and the cerebrovasculature of Alzheimer's disease are self-aggregating moieties termed A4 protein1 and βprotein2,3, respectively. A putative A4 amyloid precursor (herein termed A4695) has been characterized by analysis of a human brain complementary DNA4. We report here the sequence of a closely related amyloid cDNA, A4751,distinguished from A4695 by the presence of a 168 base-pair (bp) sequence which adds 57 amino acids to, and removes one residue from, the predicted A4 695protein. The peptide predicted from this insert is very similar to the Kunitz family of serine proteinase inhibitors. The two A4-specific messenger RNAs are differentially expressed: in a limited survey, A4751 mRNA appears to be ubiquitous, whereas A4695 mRNA has a restricted pattern of expression which includes cells from neuronal tissue. These data may have significant implications for understanding amyloid deposition in Alzheimer's disease.

A new A4 amyloid mRNA contains a domain homologous to serine proteinase inhibitors.

Atrial extracts contain factors which induce potent natriuresis1,2 changes in renal haemodynamics3, and relax pre-contracted vascular smooth muscle3–5. Low-molecular-weight peptides which mimic these actions have now been purified by several groups1,2,6–12, including ours (see accompanying paper9), and higher-molecular-weight proteins with similar but less potent biological activities have also been identified and are presumed to be precursors6,7,9–12. If released into the circulation, these peptides, collectively called atrial natriuretic factor (ANF), may play a significant part in blood-pressure homeostasis, regulation of extracellular fluid volume and as antagonists to the hypertensive effects of the reninangiotensin system and other hormonal and neurotransmitter systems. We describe here the isolation and characterization of rat atrial cDNA clones which encode ANF. Nucleotide sequence analysis shows that auriculin9 corresponds to the 25 amino acids located close to the C-terminus of a 152-amino acid ANF precursor. Analysis of the in vitro translation products of precursor ANF mRNA suggests that multiple forms of the precursor may exist.

Cloning and sequence analysis of the cDNA for the rat atrial natriuretic factor precursor.

Heparin-binding EGF-like growth factor : characterization of rat and mouse cDNA clones, protein domain conservation across species, and transcript expression in tissues

Judy Miller

Papers

A heparin-binding growth factor secreted by macrophage-like cells that is related to EGF.

A new A4 amyloid mRNA contains a domain homologous to serine proteinase inhibitors.

Cloning and sequence analysis of the cDNA for the rat atrial natriuretic factor precursor.

Heparin-binding EGF-like growth factor : characterization of rat and mouse cDNA clones, protein domain conservation across species, and transcript expression in tissues

A new A4 amyloid mRNA contains a domain homologous to serine protease inhibitors